RE: Suggested 4 stroke equivalent
What is the profile plane you have?
if it is a 3D type or stunt plane then...
Usually the smaller profile planes are intended to be very light so they have a light wing loading to perform best.
The Saito FA40a actually weights slightly less than a ThunderTiger 36 pro. So it would be a good candidate. The other 4 strokes tend to weigh noticeably more than the 2 stroke engines weigh.